A real-estate lock box is a padlock-shaped box that hangs around the doorknob of a residence that is on the market. The device holds the keys to a residence to allow communal access for all real estate agents, buyers, and contractors while continuing to keep the property secure.
Real estate lock boxes are generally secured either with a manual key, a security code, or a swipe card. Some real estate lock boxes allow owners to know when the residence has been accessed.